An example of a film-plated memory wire is disclosed in U.S. Pat. No. 3,736,576. Known types of film-plated memory wires are of uniform diameter throughout the length thereof with a very smooth surface in order to realize as large an output voltage from the wire as possible. The memory wire of the present invention is made to have a controlled roughness in order to improve the adjacent bit disturb characteristics of the continuously plated wire. This textured surface increases the effective distance between adjacent bits and thus reduces the creep tendency. One drawback in the use of a textured surface is that a lower output voltage is obtainable from the wire.
According to the present invention, techniques are employed which increase the effective "distance" between adjacent bits of the memory wire while maintaining a smooth surface without sacrifice of output voltage. Stated another way, in the film-plated wire of the present invention the magnetic path length as measured along the wire surface in a longitudinal cross-section of the memory wire is longer than that of a normal known type plated-wire of smooth surface having a straight line magnetic path.
The terminology "adjacent bits" refers to adjacent areas of the wire used to store information magnetically. In plated memory wire which has its magnetic layer (or layers) deposited in a continuous manner, adjacent storage areas of the wire have a tendency to interact or disturb the stored value of each other, and this tendency is referred to as "bit disturb". The level and sense (or direction) of magnetization of a specific storage area can be "written"at such a magnitude as to impinge or "creep" into the adjacent magnetized area.